REMOTE CONTROLLER, COMMUNICATION-ENVIRONMENT SENDING DEVICE, AND COMMUNICATION-ENVIRONMENT CHECK METHOD

A remote controller according to an aspect of the present invention includes a speaker, an information receiver, a controller, and a display. The speaker sends an ultrasonic signal that controls an action of an in-vehicle device. The information receiver detects information related to noise sound inside a vehicle. The controller calculates propagability index of the ultrasonic signal from the information related to noise sound. The display displays the propagability index as communication quality level of the ultrasonic signal.